Sewage treatment involves removal of contaminants and harmful elements from waste water, which is primarily discharged from households. Industrially viable waste water is produced by removal of contaminants through biological, physical and chemical processes.
Sewage, generally speaking, refers to waste water from household toilets, showers, baths, kitchens and sinks that drain into the sewers. Industrial liquid waste from power plants and refineries can also be termed as sewage. Industrial sewage differs from household sewage in its content. Industrial sewage often contains waste that is harmful to the environment if left untreated, whereas household sewage would cause general accumulation of waste water that leads to mosquitoes breeding, which in turn, can bring forth a plethora of diseases.
The most basic aim of any water treatment plant is to produce an affluent which causes as little harm as possible when released into the environment, hence reducing pollution caused by releasing untreated waste water into the surrounding environment.
Pretreatment is used to remove all substances from the sewage that may clog or damage the sewage carrying lines. This is done automatically by a mechanical screen bar in modern plants that serve big populations. The solid waste collected is either incinerated or disposed off in landfills.
Sewage treatment involves three main stages:
Primary treatment: This involves temporarily storing the sewage in a sedimentation basin where the solids can settle down to the bottom while fluids such as grease, oil and lighter solids float up to the surface. This separation allows floating and settled materials to be removed and the liquid can be either discharged or sent for secondary treatment.
Secondary treatment: This process removes suspended and dissolved organic matter. It is performed by indigenous micro-organisms in a controlled environment. Secondary treatment may require a step to separate the micro-organisms from the treated water before discharge or further treatment.
Tertiary treatment: This step is performed only when the water is to be discharged into a fragile or sensitive ecosystem like an estuary, low flow river or coral reef. Water is either disinfected physically or chemically using lagoons or microfiltration before discharging it into any water body like a river, stream or bay.
Odors emitted by a sewage plant are an indication of an anaerobic or septic environment. Early stages are more likely to produce foul smelling gases such as hydrogen sulphide. If the plant is near an urban area, then carbon reactors are used to treat the odours.
A conventional water treatment plant in Cork uses 30% of its annual operating cost on energy requirements. The requirements vary with type of treatment plant. For example, plants near wetlands have lower energy requirement than plants near urban areas because cost of transportation of water through pumps to water bodies is reduced. Similarly, treatment plants that produce biogas from anaerobic digestion can meet all their energy requirements in-house.
Rainwater harvesting typically involves accumulating water and it is a practice whose origins can be traced back to thousands of years. It is highly beneficial when it comes to preserving water for later requirements in places where there is substantial scarcity of water. In the recent times, the practice of rainwater harvesting has become extremely popular throughout Ireland, particularly in places like Cork, Kerry and other major regions. This is primarily due to the inability of groundwater to fulfill the needs of homeowners and businesses.
Apart from preservation, there are various other practical benefits of rainwater harvesting, the most important ones from among which have been discussed below:
Compared to other intricate water storage methods, rainwater harvesting is very easy. All one needs are a simple tap or pipe system, storage tanks and a collection system. If you are a homeowner, you just need to install rain gutters on your roof & direct the runoff into a storage tank, and that’s it.
Free & Clean Source
This is perhaps the most important perk of rainwater harvesting. First of all, nobody is going to charge you anything for the water that you will be getting, which would help you to make great savings on your annual bills. Secondly, there is no need to worry about presence of harmful chemicals and other pollutants.
Usage of harvested rainwater for various household and business requisites aids a great deal in reducing individual carbon footprints. The same water can also be utilized for flushing toilets and washing cars, which in turn would allow perfectly clean & potable water to be employed for cooking & drinking purposes.
Since the water collected from rains is generally devoid of minerals and toxins, it can be easily used for various purposes. It is perfect for household chores like watering plants, washing cars, cleaning the driveway & patio areas, filling up a pond, and so on.
Excellent For Agriculture
Most sources of groundwater contain different types of chemicals, which make them rather unsuitable for agricultural use. But same is not the case with rainwater, as it is free from chemicals. Besides that, its utilization for agricultural purposes also reduces flooding and erosion by decreasing runoffs when there is heavy rainfall. And this, in the long run, also brings down pollution of rivers and lakes.
So if you wish to reap all these benefits, then go ahead and opt for rainwater harvesting today.